The Conservation Area was originally designated as 'The Burgh of Thurso Conservation Areas' by Thurso Town Council with effect from 04/02/1970 and included five separate areas. Most of these were within the core of the town but an additional area existed around the property known as Pennyland to the northwest. As of 13/03/1974 the area was expanded slightly by joining what had been the area around Old St Peters Kirk in the north of the town (Area 1) to the core of the town (Area 5). Later changes rationalised the remaining areas into a single area, which included reducing Area 2 which had spanned the Thurso River and removed Pennylands which had by that time also been designated as a Listed Building. Later still, the area around St Andrew's Church was also included. All previous designations were cancelled with effect from 28/02/1987 when Thurso was re-designated as a single Conservation Area. The re-designation was eventually published in the Edinburgh Gazette on 19/01/2001.